code: def state_batch_axis(self):
      ret = []
      for i in range(self.num_layers):
          if self.recurrent:
              layer = self.layers[0]
          else:
              layer = self.layers[i]
          ret.append(layer.state_batch_axis)
      return ret
  
imports: from typing import Union, Optional, List
  from torch import nn
  import torch
  from ..layers import PositionwiseFFN
  from ..attention_cell import MultiHeadAttentionCell, gen_mem_attn_mask, gen_self_attn_mask
  from ..utils import to_torch_dtype
label_desc: Use image node_id 5 for calling the TransformerDecoder obj's underlying member method code with example usage: obj.state_batch_axis() and returns: ret